The Frequency of HIV-1 infections was examined by PCR in a cohort of seronegative individuals with hemophilia who had been exposed to contaminated blood products prior to the implementation of donor screening and viral inactivation procedures. 57 HIV antibody negative persons who were repeatedly exposed to clotting factor concentrates were studied. Samples were analyzed by p24 antigen assays, antibody assays, virus culture and PCR. HIV-1 proviral DNA was detected in only 1 out of 57 seronegative recipients of clotting factor concentrates. The fringing that only 1/57 patients that were repeatedly exposed but remained seronegative had evidence of silent HIV infection as analyzed by PCR suggests that latent infections may be relatively uncommon in multitransfused, seronegative persons with hemophilia.